In the optical computer mouse field, the optoelectronic module can include at least one photoreceptor circuit mounted on a substrate and enclosed in an opaque plastic mould or encapsulated. A light passage is made in the plastic mould in the shape of a diaphragm above a photosensitive area of the photoreceptor circuit. This light passage thus enables the circuit to pick up the light generally reflected on a work surface of the computer mouse. This light is produced by a light source arranged in the computer mouse case. The light source may also be a light source circuit mounted on the substrate below a through aperture of the plastic optoelectronic module mould.
Usually, a state of the art optoelectronic module for a computer mouse takes the form of a standard encapsulated DIL type component, as disclosed for example in EP Patent Application Nos. 1 339 012 and 1 361 537. This component includes regularly spaced pins coming out of a plastic mould inside which the photoreceptor circuit and possibly a light source circuit are arranged. The connection pins of the module can be inserted in metallised holes of a mother printed circuit board housed inside the computer mouse. An aperture in the mother printed circuit board is also provided between the connection pins of the module in order to allow the emission of light from the light source circuit and the reception of light reflected by the photoreceptor circuit.
This optoelectronic module may include or be mounted on a transparent optical lens unit, which is preferably secured above a wide aperture in the bottom of the computer mouse case. It is thus important to adjust the height of the optoelectronic module, mounted on the transparent optical lens unit, on the mother board relative to the work surface or to the bottom of the computer mouse case. This adjustment of the module height relative to the mother board is carried out prior to electrical connection for example by welding the connecting pins of said module in the metallised holes of the board. In some cases, a part of the connecting pins that overshoots the metallised holes, can be cut. Such operations prove relatively long and thus expensive, and are difficult to implement in practice for mounting the optoelectronic module in the computer mouse case, which is a drawback.
The optoelectronic module made in the form of a DIL type component is moreover relatively voluminous given that the spacing of the connecting pins is well defined, which is another drawback. Moreover, only the height of the module can be adjusted to secure it as a function of the spacing between the mother board and the bottom of the mouse case onto which the transparent optical lens unit might be secured. This also requires adjustment of the mother board relative to the place where the transparent optical lens unit of the optoelectronic module is to be secured or placed, which is disadvantageous.